The Federal Circuit recently decided an IPR dispute between HTC Corp., and Cellular Communications Equipment LLC. The patent at issue related to determining a transmit power difference to be maintained by a subscriber station between a total maximum transmit power of the subscriber station for the codes, and a total transmit power of the subscriber station for the codes at a start of a message transmission using a first one of the codes. At issue was the requirement of the claims related to the "start of a message transmission" element. Claim 1 is reproduced below:

1. A method for operating a radio communication system in which a subscriber station is assigned a plurality of codes for transmitting messages, comprising: determining a transmit power difference which is to be maintained by the subscriber station between on one hand a total maximum transmit power of the subscriber station for the codes and on another hand a total transmit power of the subscriber station for the codes at a start of a message transmission using a first one of the codes.

HTC alleged that one of the cited references inherently disclosed the limitation because the start of a frame preceding an ACK/NACK signal, if it happened enough, would eventually correspond to the start of a message transmission.

Examiners often make similar arguments with regard to claim limitations that require a specific timing for certain events. Often Examiners cite references that show the action, but not at the claimed time. Nevertheless, Examiners cite the reference as inherently disclosing the element since there could be a time when the action occurs at the specified time.

However, this case confirms the well established rule that mere possibilities are not sufficient to establish inherency. By definition the idea that there could be a time when the action happens to occur at the claimed instance is reliant on "mere possibilities" and contrary to controlling case law on inherency. So, when an Examiner rejects claim elements with reasoning like HTC's, patent practitioners should be steadfast in pushing back against the USPTO.